Camera systems have been proposed which take a 3D image by taking right-eye and left-eye parallax images using two lens devices disposed in parallel. The two lens devices used in such camera systems are driven simultaneously so that sets of optical conditions which are varied by a focusing control, a zooming control, an iris control, etc. are always kept identical. In general, the right-eye and left-eye lens devices of such camera systems are completely identical in terms of the shooting lens specification (the shooting lenses are of the same kind).
That is, to take a 3D image, it is necessary to prepare two completely identical lens devices. Even if a user owns plural lens devices, the lens devices cannot be used for taking of a 3D image as they are.
In this connection, the 3D shooting system disclosed in Patent document 1 is known as a camera system which uses various lens devices for 3D and equalizes zoom positions (focal lengths).